Gem-grinding apparatus.



A. BOERNER.

GEM GRINDING APPARATUS.

APPLICATION FILED JUNE 5 1918.

1 ,3 1 4,785 Patented Sept. 2, 1919.

UNITE STATES PATENT OFFICE.

.ARNO BOERNER, OF SCHEVENIN GEN, NETHERLANDS, ASSIGNOR TO NAAMLOOZE VENNOOTSCHAP OCTROOI MAATSCHAPPIJ HOLLAND TOT EXPLOITATIE .VAN UITVINDINGEN, OF AMSTERDAM, NETHERLANDS, A COMPANY OF THE NETHERLANDS.

GEM-GRINDING APPARATUS.

Specification of Letters Patent.

Patented Sept. 2, 1919.

To all whom it may concern:

Be it known that I, ARNO BOERNER, originally a subject of the Emperor of Germany, but having lost my nationalit owing to the fact that I have'resided outsic e of Germany for more than thirteen years without interruption and without ever giving notice to the German legations or consulates, residing at Scheveningen, the Netherlands, have invented certain new and useful Improvements in Gem-Grinding Apparatus, of which the following is a specification.

This invention relates to an apparatus for polishing diamonds and other precious stones and has for its object to provide'an apparatus of this 'class in which by a simple adjustment quickly made pressure on the stone being out, against the grinding me ternal slide ribs 2, 2 along which a sl1de 3 is adapted to be displaced in a horizontal d1 dium, may be Varied at will, and in which the jewel is so held that it may be inspected at any'timeby simply removing from the 'remainder of the apparatus the jewel holding member, which may be quickly returned,

placing thereby the jewel in exactly the same position relatively to the grindlng medium as it previously occupied.

The annexed drawings illustrate the invention; in these drawings: Figure 1 is a perspective View, Fig. 2 a side elevation, and Fig. 3 a plan view of a tool 1 n accordance with the invention, Fig. '4 being a sectional view along A--A in Fig. 3.

r The apparatus comprises a horizontal guide-piece 1 which is secured to a table (not shown) and provided w1th V-shaped exrection. The said slide 3 is provided with a knob 4 by which it may be displaced by hand and which has a screw connection w1th the slide, so that the latter may be secured in any desired position relative to the guide- The slide3,in its turn, serves as a guideposition relative to the slide 3, its front end is provided with a hook or claw 7, whlch fits a wedge-shaped projection 8 of the slide 3.

Thesaid projection 8 has a recess 9 for reabout the shaft 12 the one independent of the other the arm 14carries a laterally extendlng pm 15 which enters a slot 16 cut in the arm 13 concentrically with the shaft 12, 1n such a manner, that the arm 14, from the .p0S1t1011 shown in the drawin may be pressed down withoutengaging t e arm 13, while at a movement in the reverse direction the arms are coupled together.

The arm 14 has a somewhat enlarged right hand end portion, and secured to its bottom, is a plate 17 with a stub pin 18 for holding a coiled spring 19, whose bottom end is seated on a plate 20 with stub pin 21. The plate 20 is secured to a screw bolt 22 with a nut 23 located between two plates 24, 24 secured to the slide 5.

Pivotally mounted within a slot 25 of the arm 14 is a pawl 26, which is provided with a handle 27'at its top, and havingaprojec- I tion 28 at its bottom end. When the arm 14 is'pressed down, the said projection 28 is the arm 14 a handle 30 is secured to the slide 5. 1

At the left hand side of the bracket 11 is a micrometer screw adapted to be raised and lowered by means of a nut 32. The top of said screw 31 is formed as a spherical head 33, adapted to be screwed up until it engages the bottom face of the arm 13 of the tongs.

The front end of the arm 13 carries a dop 34 for receiving one or a plurality of stones to be polished on the lapping wheel 35.

Secured to the rear portion of the arm 13 is a finger 36, which has an enlarged portion serving as a support for the thumb.

The operation 9f the device is as follows:

Assuming that the polisher has withdrawn the slide 5 with the partsattached thereto from the slide 3 and that one or a plurality of stones have beenset in the d-op, also,"that the arm 14: has been pressed down and that it is locked in this position owing to the coaction of the projections 28 and 29 the polisher then replaces the slide 5 between the ridges 6, 6*, until the hook 7 engages the projection 8, and the pin 10 contacts with the edges of the recess 9, during which oper-' ation' he grasps the rear portion of the arm 14 with the palm of hi? hand, taking hold of the handle 30 with his four fingers, his thumb pressing down the finger 36. The micrometer screw 31 shouldassume a position so as to allow the arm13 to be support, ed' by the head 33 and the stone tov be clear of the lap 35 if the polishers thumbreleases the finger 36. g This being done,-the'micrometer screw may be turned down so far that the stone engages the lap. 35 and, besides, is free todescend through a distance required for the polishing of the particular facet to be out. By exerting a suitable pressure onthe handle 27 the polisher now releases the pawl 26, so that the coiled spring 19 forces the arm 14 upward and thelatter transmits its pressure to the stone through the medium of the pin 15. The pressure of the stone on the lap may be adjusted by raising or lowering the supporting plate 20 by means of thenut 23, I

Should it be required for the stone tobe positioned at a greater or at a smallerdistance, from the center of the lap, all that the polisher has to do after having lifted the stone by means of the finger 36 and released the screw 4, is to displace the slide 3 in the required direction and through thecorrect distance, and then to secure it in its new position.

' Examining the progress offthe work hardly takes any time. Afterthe 'arm ll 4 hasbeen pressed down against the action of the spring 19, and after it. has been locked by the pawl 26 (the stone being at the same timelifted clear of the lap by ajpressure of the thumb, on the finger- 36), the polisher may withdraw the slide 5 from the slide 3 by moving it, toward the center of the lap 35 and then lift it. Replacing the tongs in their correct position is effected in a quite as simple manner; owing to the coaction of the hoe-k7 with the projection 8, the stone necessarily reassumes exactly the same position relative to the lap, and after the releasing of the pawl26 the stone willexert on the lap exactly the same pressure as before; A a

If the pressure of the stone on the lap is to be increased or decreased to avery high degree, the. coiled spring 19, which is loosely seated on the plates 17 and 20 and guided by the stubpins 18 and 21, may be removed and replaced by a stronger or aweakervone.

As a matter of course the apparatus described above may bemodified in various respects Without the desired operation being interfered with. 1

WhatI claim as my invention and desire i to secure by Letters Patent is :I i v 1. In apparatus ofthe class described, arms rotatably mounted" on1- a shaft, means carried by one of the said arms for holding the stone to be polished, resilient means 2. In apparatus'of the type referred to, a

lever comprising two independent armsro- 'ta'tably mounted on a shaft, means-carried vby one of the said lever arms for holding the stone to be polished, resilient means tending to impart upward movement to the second lever arm, and means whereby the second lever arm is adapted to move downward independent of the first lever arm, but to engage the latteron being moved in the reverse direction.

3, In apparatus of the type referredto, two arms rotatably' mounted on a shaft,

means carried byone of the arms for holding the stone to be polished, a coiled spring tending to impart upward movement to the second arm, means for adjusting the trim e sion of said coiled spring, and means whereby the second isadapted to-move downward independent of the first am, but

to engage f the latter on being movedin the reverse direction i it i 4. In apparatus of the type referred to, two arms ro'tatably mounted on a shaft supported on a baseplate, aslide on which the said base plate is adapted'to be lengthwise displaced, a guide piece for said slide, means for the said, slide in a predetermined position on "the said guide piece, means carried by one of the arms for holde ing the stone to be polished, resilient means tending to impart upward movement to the second arm, and means whereby thesecond arm is adapted to move downward inde' pendent of the first arm, but to engage the latter on fbeing moved in the reverse direction.

5. apparatus of the type referred-to, two arms rotatably mounted ona shaft's'upported on abase plate,means carried by one. ofthe arms for holding the stone to be polished, resilient means. tending to impart' upward movement to the 'seoondarm, a member secured were first amafiaextefia ing alongside the second arm so as to be adapted to be engaged by the thumb of the operative when grasping the said second arm, and means whereby the second arm is adapted to move downward independent of the first arm, but to engage the latter on being moved in the reverse direction.

6. In apparatus of the type referred to, two arms rotatably mounted on a shaft supported on a base plate, means carried by one of the arms for holding the stone to be polished, resilient means tending to impart upward movement to the second arm, a member secured to the first arm and extending alongside the second arm, so as to be adapt .ed to be engaged by the thumb of the operative when grasping the said second arm, a pawl rotata ly mounted on the said second arm at the side of said member, a projection on the base plate adapted to coact with the saidpawl, and means whereby the second arm is adapted to move downward independent of the first arm, but to engage the latter on being moved in the reverse direction.

7. In apparatus of the type referred to, two arms rotatably mounted on a shaft, means carried by one of the arms for holding the stone to be polished, a coiled spring tending to impart upward movement to the second arm, a slot in the first mentioned arm, a laterally extending pin on the second arm, the said pin being received in and coacting with the said slot in such a manner that the second arm is adapted to move downward independent of the first arm, but to engage the latter on being moved in the reverse direction.

In testimony whereof I have affixed my signature in presence of two witnesses.

ARNO BOERNER.

Witnesses H. VERHAGEN, Jr., PLANTE FIEBURE.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents, Washington, D. 0. 

